<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    let score = +prompt('请输入成绩查看相关评价：')
    if (score >= 90) {
      alert('你很优秀')
    } else if (score >= 70) {
      alert('不错，继续加油')
    } else if (score >= 60) {
      alert('及格了，需要努力了哈')
    } else {
      alert('有点差啊')
    }
  </script>
</body>

</html>